(1) Field of the Invention
The compounds this invention provides are novel Cablocker-type cardiovascular agents having potent antihypertensive and coronary vasodilating effects, and useful in treatment for cardiovascular diseases such as angina pectoris, hypertension, cerebrovascular dysfunction, arrhythmia or the like.
(2) Prior Art
Compounds having Ca-blocking effect have commonly been used for treatment of cardiovascular diseases such as angina pectoris, hypertention, cerebrovascular dysfunction, arrhythmia or the like, and have become well-known because of their high efficacy. In particular, a series of 1,4-dihydropyridine derivatives have been investigated extensively and developed as Ca-blocker. Examples of useful Ca-blockers are Nifedipine (U.S. Pat. Nos. 3,485,847 and 3,644,627), Nisoldipine (Japanese Patent Publication No. 56-47185), 2-amino-1,4-dihydropyridine derivatives (JPN Pat. Pub. No. 57-20306), Nicardipine (JPN Unexamined Pat. Pub. No. 49-109384), 2-pyridyl-1,4-dihydropyridine derivatives (JPN Unexam. Pat. Pub. No. 54-48796), 2-methyldihydropyridine derivatives (JPN Unexam. Pat. Pub. No. 55-62065) and the like. Some examples of pyrazolodihydropyridine derivatives, the production thereof and their Ca-blocking action are disclosed in JPN Pat. Application Nos. 57-176763 and 58-166258 by the present inventors.